Conventionally, polyimide resins having excellent heat resistance, electric property and mechanical property have been used for surface protection films and interlayer insulation films for semiconductor elements. However, as semiconductor elements are being required to have higher integration and larger size in recent years, there is a demand for thin and small sealing resin packages. In order to meet the demand, a surface mounting system by LOC (lead on chip) and solder reflow are being employed, and there is an increasing demand for a polyimide resin that has ever better mechanical property and heat resistance.
A photosensitive polyimide obtained by imparting a photosensitive property to the polyimide resin itself has been recently used. Use of such a product realizes simple pattern production steps and shortening of the complicated production process. Conventional photosensitive polyimide, a heat resistant photoresist obtained by using a precursor thereof and their uses are well known. Concerning negative photosensitive polyimide, there are findings such as a method of introducing a methacryloyl group into a polyimide precursor through an ester bond or an ionic bond (e.g., see Patent Documents 1 to 4), soluble polyimide having photopolymerizable olefin (e.g., see Patent Documents 5 to 10), and self-sensitized type polyimide having a benzophenone skeleton and having an alkyl group at an ortho position of an aromatic ring to which a nitrogen atom is bound (e.g., see patent Documents 11 and 12).
Development of the aforementioned negative photosensitive polyimide requires an organic solvent such as N-methylpyrrolidone. Therefore, recently there has been a proposal of a positive photosensitive resin that can be developed in an alkaline aqueous solution. Concerning the positive photosensitive resins, there have been findings such as a method of introducing an o-nitrobenzyl group into a polyimide precursor through an ester bond (e.g., see Nonpatent Document 1), a method of mixing a naphthoquinone diazide compound with soluble hydroxylimine or a polyoxazole precursor (e.g., see Patent Documents 13 and 14), a method of introducing naphthoquinone diazide into soluble polyimide through an ester bond (e.g., see Nonpatent Document 2) and a method of mixing naphthoquinone diazide with an polyimide precursor (e.g., see Patent Document 15).
However, the aforementioned negative photosensitive polyimide has a problem with its resolution due to its mode of function. The negative photosensitive polyimide also causes a problem of possible reduced yield ratio upon production depending on its use. In addition, since possible structures of the aforementioned polyimide for use are limited, the variety in physical property of the finally obtained coating film is limited and therefore the negative photosensitive polyimide is not suitable for multipurpose uses. Meanwhile, as mentioned above, the positive photosensitive polyimide also has similar problems such as low sensitivity, low resolution and limitation on its structures due to its problem accompanied with absorption wavelength of the photosensitizing agents.
There are other products to which a phenolic hydroxyl group is introduced in place of carboxylic acid, e.g., a mixture of a polybenzoxazole precursor and a diazonaphthoquinone compound (see e.g., Patent Document 16) and a polyamide acid to which a phenol moiety is introduced through an ester bond (see e.g., Patent Document 17). However, these have an insufficient development property, and therefore cause film thickness reduction at a portion that are unexposed to light, and also cause delamination of the resin from the substrate. Aiming at improvement of the development property and adhesion, there has been proposed a product containing a polyamide acid having a siloxane moiety in a polymer skeleton (see e.g., patent Documents 18 and 19), although, as discussed above, addition of the polyamide acid deteriorates storage stability. In addition, aiming at improvement of storage stability and adhesion, there has also been proposed a product in which the amine terminal group is capped with a polymerizable group (see Patent Documents 20 to 22). However, since this product uses a diazoquinone compound containing abundant aromatic rings as an acid generator, the product has poor sensitivity. Then, since there is a necessity to add a large amount of diazoquinone compound, the mechanical physical property of that product after thermal curing is remarkably reduced. Thus, this product cannot be recognized as a material having a practical level of properties.    Patent Document 1: JP Sho-49-115541-A    Patent Document 2: JP Sho-51-40922-A    Patent Document 3: JP Sho-54-145794-A    Patent Document 4: JP Sho-56-38038-A    Patent Document 5: JP Sho-59-108031-A    Patent Document 6: JP Sho-59-220730-A    Patent Document 7: JP Sho-59-232122-A    Patent Document 8: JP Sho-60-6729-A    Patent Document 9: JP Sho-60-72925-A    Patent Document 10: JP Sho-61-57620-A    Patent Document 11: JP Sho-59-219330-A    Patent Document 12: JP Sho-59-231533-A    Patent Document 13: JP Sho-64-60630-A    Patent Document 14: U.S. Pat. No. 4,395,482    Patent Document 15: JP Sho-52-13315-A    Patent Document 16: JP Sho-64-46862-B    Patent Document 17: JP Hei-10-307393-A    Patent Document 18: JP Hei-4-31861-A    Patent Document 19: JP Hei-4-46345-A    Patent Document 20: JP Hei-5-197153-A    Patent Document 21: JP Hei-9-183846-A    Patent Document 22: JP 2001-183835-A    Patent Document 23: JP Hei-3-763-A    Patent Document 24: JP Hei-7-219228-A    Patent Document 25: JP Hei-10-186664-A    Patent Document 26: JP Hei-11-202489-A    Patent Document 27: JP 2001-56559-A    Patent Document 28: JP 2001-194791-A    Patent Document 29: JP 2002-526793-A    Patent Document 30: U.S. Pat. No. 6,143,467    Patent Document 31: JP 2001-125267-A    Patent Document 32: JP Hei-3-58048-A    Patent Document 33: JP Hei-3-259148-A    Patent Document 34: JP Hei-10-195294-A    Patent Document 35: JP Hei-11-202488-A    Patent Document 36: JP 2000-250209-A    Patent Document 37: JP 2001-249454-A    Patent Document 38: JP 2004-94118-A    Nonpatent Document 1: J. Macromol. Sci. Chem., A24, 12, 1407, 1987    Nonpatent Document 2: Macromolecules, 23, 4796, 1990    Nonpatent Document 3: Macromolecules, 29, 6427, 1996